TB Testing

The TB test is a skin test in which a tiny amount of purified protein derived from the TB germ is injected into the skin to see if your body recognizes the protein and produces a local inflammation at the skin site. The testing is safe and relatively painless. It is not possible to become TB infected by testing.

As it takes some time for this kind of reaction to take place, the test is “read” 48 to 72 hours after initial testing. For example, if your skin test was given on Monday, you would need to return to have it read on Wednesday.

A skin test with a reaction is read by measuring the area of induration (swelling) at the site. A test is positive for TB if the induration is greater than certain millimeter parameters when risk factors such as one's immune status and potential exposure history are taken into account.

Testing for Tuberculosis (TB) is available by appointment 660-665-8491 at ACHD located at 1001 S Jamison in Kirksville.

TB testing can be done on Mondays and Wednesdays ONLY  from 8:00 am to 4:00 pm

After the initial testing, you must return to the clinic to have the test site examined.

Initial TB Test      Return For Examination

Monday             =              Wednesday

Wednesday       =                 Friday

A $20 fee will be requested when you receive your skin test, unless the test is done because the person has been in contact with an active case. Such “contact investigation” tests are free.

A positive TB skin test as determined by the nurse when you come back to have the test “read” means that at some time in the past you were around someone with “active” Tuberculosis and have acquired a TB infection.

Positive skin tests are quite common in the United States. Randomly tested, about 1 in 100 Americans would have a positive TB skin test.

If a test is read as positive, ACHD nurses will refer you to a primary care provider for follow-up and a chest x-ray.

The chest x-ray will indicate whether you have “active” TB disease or, as is usually the case, a dormant TB infection. You and the nurse will discuss TB treatment therapy, signs and symptoms of TB, and lifestyle issues such as exercise, diet, and drug or alcohol use which may affect your health with or without treatment. All those having positive TB skin tests will be encouraged to have an HIV test.

At some time in your life you must have been around someone who had “active” Tuberculosis. This could have been a coworker, a patient in your care, a family member, etc. Data indicates that usually you must “share” the air of someone with TB for at least 8 hours to acquire the infection. The TB germ is breathed into the lungs as part of tiny droplets which float in the air after someone with “active” TB coughs or laughs. You then become infected and your skin test is evidence that your immune system has fought the TB germs that you acquired.

Once attacked by your body’s defenses, the TB germs usually become dormant (goes to sleep) and you cannot pass the germs to someone else. Later, if your immune system has been weakened by severe or chronic illness, HIV, drug or alcohol abuse, or old age, the dormant TB can “wake up” and cause Tuberculosis disease and symptoms.

Only someone with active TB disease is infectious (can pass the disease to someone else). A chest x-ray is needed to determine if the TB is active or dormant.

If a test is read as positive, ACHD nurses will refer you to a primary care provider for follow-up and a chest x-ray.

Before 1950, Tuberculosis was difficult to treat with a stigma of danger and fear attached to the diagnosis. The use of new effective antibiotics and public awareness has helped to significantly decrease the number of TB cases.

Unfortunately, memories of earlier times are hard to erase so if you test positive for TB you may experience some personal fear in yourself and from others. Rest assured, however, TB is curable and the treatment of TB infection does not usually involve separation from society as in times past.

Active TB Cases
If active TB disease is evidenced on the chest x-ray, then treatment of the disease is mandated by law to protect the public from the spread of TB. Treatment usually involves taking at least 3 pills every day for 2 months followed by 2 pills a day for another 7 months. Sputum specimens may be ordered and treatment may be adjusted by your doctor depending on the results.

Active cases are treated with “Directly Observed Therapy” (DOT) and depending on the medicines ordered, the patient will receive their medicine daily (or 2-3 times a week) from the TB nurses to assure that no doses are missed.

It is important for the person with active TB to follow the directions of the TB nurses regarding the use of masks and isolation from the general public to prevent the spread of TB until such time it is proven that the medicine has worked to make them non-infectious.

Latent (dormant) TB Cases
If a latent (dormant) TB Infection is indicated by a normal chest x-ray, treatment is voluntary and usually involves taking 2 pills (an antibiotic and a vitamin) for 9 months. Once started, the series needs to be completed to prevent the formation of antibiotic-resistant TB.

It is important to note that tuberculosis treatment requires a commitment of time and a determination to complete the drug series. The full treatment of TB infection will kill the dormant germs and prevent the development of active TB later in life.

The medicines used to treat TB are strong and can sometimes affect the liver of those taking TB therapy especially if they are over the age of 35 or have a history of alcohol abuse.

ACHD will provide all tests and medication prescribed to treat TB through the Missouri Department of Health and Senior Services Tuberculosis Program. Your physician will order the medicine and you will be given a one-month supply of medication, and must return to the clinic once a month to pick up the next month’s pills. This procedure allows the nurse an opportunity to make sure that the pills are not adversely affecting you.

Please know that once you have had a positive TB skin test you will always have a positive test whether you proceed with the treatment or not. If, in the future, you have symptoms of TB, you will need a chest x-ray to rule out an active TB disease. On completion of therapy you will receive a letter explaining this, which you can use to show to future employers, schools, etc., should you be required to get a TB test.